Determination of Total Fluoride Emissions from Stationary Sources (SPADNS Zirconium Lake Method)
This method is applicable for the determination of total fluoride (F-) emissions from stationary sources. Once collected, total fluoride is determined by analyzing the sample for F- using a spectrophotometer following the SPADNS Zirconium Lake Method. This method does not measure fluorocarbons such as Freons.
Gaseous and particulate F- are sampled isokinetically from a source using a modified Method 5 train which consists of a filter and a series of four impingers. The sampling procedures found in Method 13A are cited as the ones to use for this method. The probe may be heated to no greater than 120 +/- 14oC (248 +/- 25oF). The first two impingers are filled with 100mL of deionized water. The 3rd impinger is left empty and the 4th impinger is filled with 200-300g of silica gel. The filter specified for use is a Whatman No. 1 filter or equivalent. It is placed between the third and fourth impinger which is the deviation from Method 5.
Three filters from each lot used should be checked for F- prior to use for sampling. The filters must contain < 0.015 mg F-/cm2 in order to be acceptable for use. Glass fiber filters typically contain high or variable amount of F- and are not acceptable for use.
After collection, the contents of the impingers are measured and transferred to a polyethylene bottle. The filter is added to the same container. The probe, liner, filter holder, impingers, and connecting glassware are rinsed with deionized water and added to the same container. The method specifies using in total <500mL of deionized water for the train rinse. The silica gel can be weighed in the field to determine the moisture content of the stack gas.
This method requires that samples be prepared using distillation. As a cost saving measure, many laboratories do not perform the distillation step, however, the method does require this distillation step. Total F- is determined colorimetrically using the SPADNS Zirconium Lake Method.
(EPA 40CFR Part 60 Appendix A)